1. Field of the Invention
This invention relates to aircraft display devices.
More particularly the invention relates to display devices suitable for use as standby attitude reference displays in aircraft.
2. Description of Related Art
The provision of a standby attitude reference display in a modern aircraft cockpit poses a number of problems. The conventional standby electromechanical gyro instrumentation has low reliability leading to high maintenance costs and the possibility of uncertainty as to which instrument to follow when only one standby is available as is often the case in a fighter aircraft due to considerations of cockpit space.
To meet this problem it has been proposed to use for a standby attitude reference a high reliability display device, such as a liquid crystal display, comprising an array of selectively activatable fixed display elements, and to control the selective activation of elements using appropriate ones of the range of aircraft body motion sensors which are incorporated in the complex flight control and other systems provided in modern aircraft.
The difficulty then arises of obtaining with such a relatively simple display device, a display which permits easy transition from the primary attitude display and fits ergonomically into cockpit operation, and which presents to a pilot a readily interpretable, unambiguous and natural attitude representation. In this connection it is desirable in a modern aircraft that the standby attitude reference display should not merely be capable of use as a `get you home` facility, but should also be capable of use as a recovery instrument i.e. to enable the pilot to recover the aircraft from extreme attitudes.